DMX light questions

[zorn]

OK, so there are dmx controllers and dmx to usb dongles if you want to connect to PC and use a PC program instead of a real controller.
If i buy the latter, do i need to buy one for every single dmx light I'll want to use, or can I "daisy chain" the rest to the one which is connected to the PC with the dongle?

[colouredmirrorball]

Daisy chaining is the way it's done.

[colouredmirrorball]

That depends on multiple factors, like amount of noise, cable length, cable and interface quality, terminator at the end, ...
If you start to get errors, you'll need a booster or another controller (if software allows it).

[dkumpula]

uh i think 3-4 in a room shouldnt be a problem right?
where can i learn all this?

EDIT: i wish we could also use daisy chaning for ILDA lasers and still have each laser display different pattern.

You can easily run 300 feet or more of DMX cable without needing repeaters. The number of daisy chained devices you can include before you have trouble with signal degradation depends on the devices you include. Some devices can eat up a good deal of the DMX signal. That said, I do not run into problems until I have 20 or more devices chained together.

The real DMX expertise can be found in the blue room web site.

David

[Datsurb]

To get a basic understandig of DMX, i used youtube. Search DMX 101 or DMX lessons e.g.
I found out that "freestyler" is more than usefull for controlling 5-10 units. It has a learningcurve as all SW, but once you get the basic understanding, you will master it.

Ny advice is to get lightningequipment that have a "name" like Martin or American DJ, as a lot of theese have profiles in Freestyler, and you do not need to make them yourselves, unless you like that too.

For DMX controller, go for enttec pro, as this is more or less supportet into all SW. If lasers is hobby #1, i guess you already have, or plan to get Pangolin SW. Enttec pro is supprted and can be used directly in e.g Quickshow.

Espen

[norty303]

DMX512 if it complies with the standard should support at least 32 fixtures per chain.

[depo]

It all depends on how many channels your fixtures have. One Universe is 512 channels so if you have par cans run off dimmers you can have 512 of them on one universe. If you have moving heads you can have more like 32 to 36 fixtures (as norty said) depending on what mover.

Instead of daisy chaining each fixture you are better off using DMX splitters. You will be able to run more fixtures of the one universe before getting errors.

[colouredmirrorball]

Instead of daisy chaining each fixture you are better off using DMX splitters. You will be able to run more fixtures of the one universe before getting errors.

You make it sound like he needs a splitter for every fixture. Shouldn't be needed for 4 or 5 lights.

[depo]

You make it sound like he needs a splitter for every fixture. Shouldn't be needed for 4 or 5 lights.

True. I'll rephrase. "Instead of daisy chaining each fixture you can use a DMX splitter at back of house run 1 DMX run left stage and 1 dmx run right stage and you have buffered signal each side of the stage."

He asked if there was a limit to the number of lights that you can daisy chain. And daisy chaining a full universe of lights with no DMX splitter on a pc based dongle will cause errors. Especially if you have cheaper fixtures.

[norty303]

He asked if there was a limit to the number of lights that you can daisy chain.

As per my previous response, its 32 according to the standard.

Number of DMX channels used for those 32 fixtures is irrelevent, so it could be 32 or it could be the full 512. Depending on your desk, the packet size may not change between the 2 scenarios, on some it might.
Obviously, if the channel count of the 32 fixtures is >512 then the channel limit will be your deciding factor.

Purely from a cable management and fault finding perspective a buffered splitter is very useful, as you've described.

It's probably also worth stressing to the OP that when talking about 'splitters' these are not passive Y splits - you can passive split, but it goes against the standard and is generally ill advised. A 4 way splitter is cheap (~£70) and a great addition to any lighting guys box.

P.S. Depo, i see you're from Wollongong, is it a big place? Its had more than its fair share of world champion motorbike racers over the years!